Tobacco treatment



United States atent O 2,739,600 TOBACCO TREATMENT Ludwig A. Staib, Jr., Elizabeth, N. J., assignor to Ameri- No Drawing. Application July 1, 1055, Serial No. 519,668

8 Claims. (Cl. 131-142) This invention relates to the manufacture of tobacco sheet material by the combination of finely divided tobacco with an adhesive substance. More particularly, this invention relates to the treatment of tobacco by heat and chemicals prior to its contact with adhesive material in the manufacture of tobacco sheets.

In the manufacture of tobacco sheet material finely divided tobacco is contacted with an adhesive dispersion and dried into the form of a sheet. In commercial practice it has been found that some varieties of tobacco when brought into contact with viscous adhesive dispersions adversely afiect the viscosity of these dispersions. On the other hand, some tobacco appears to leave these dispersions substantially unaffected. The property of adversely affecting the viscous and adhesive qualities of viscous adhesive dispersions appears to be unrelated to other recognized characteristics of the tobacco. Tobacco which has undesirable effects upon adhesive material is known as microbiologically active tobacco. Other tobacco is by contrast undesignated.

Accordingly, it is an object of this invention to provide a method of treating microbiologically active tobacco so as to neutralize its objectionable properties in the manufacture of tobacco sheets.

The advantages of this invention are realized by treating finely divided tobacco prior to contact with adhesive material either by exposure to an aqueous aldehyde solution or by exposure to a controlled duration of heating or a combination of these two techniques. It is a feature of this invention that tobacco treated according to this method can be stored in contact with adhesive material, for example as a slurry, for many hours or even for several days when proper sterilization precautions are taken. Heretofore, the viscous adhesive properties of such dispersions often dissipated within a few hours.

As a working theory of this invention it is postulated that certain microbiologically active materials occur in natural tobacco leaf which disrupt the structure of adhesive chemicals such as polymers. By exposure to controlled heating and to chemicals such as formaldehyde, mierobiologically active materials, such as protein enzymes, are suificiently denatured to make the tobacco usable in conjunction with such polysaccharide adhesives as carboxymethyl cellulose and hydroxyethyl cellulose. However, this invention is broadly applicable to the treatment of tobacco for use with polysaccharide adhesives.

When tobacco sheet material is manufactured according to the suspension or slurry technique, dry ground finely divided tobacco is mingled with an adhesive slurry of sodium carboxymethyl cellulose, for example, to form a viscous mass and is spread out to form a sheet by calendering or casting, for example. When sheet material is manufactured according to this method it is often convenient to store a slurry of tobacco and adhesive material for a few hours before the viscous mass is subjected to film forming operations. Prior to this invention certain tobaccos altered the adhesive and viscous 2,739,600 Patented Mar. 27, 1956 properties of the tobacco adhesive slurries and required the addition of more adhesive material prior to the film forming operations. Consequently, this invention eifects an economy in adhesive material in the manufacture of sheet material.

Among the aldehyde preparations which can be used in the treatment of tobacco according to this invention are formaldehyde, glyoxal, trioxymethylene, and acetaldehyde. The use of other aldehyde material is also contemplated by this invention. It is convenient to apply the aldehyde material to tobacco in an aqueous solution together with aldehyde vapor. For example, formalin (30% formaldehyde solution) may be used.

Moreover, the tobacco can be subjected to heat either independently of the chemical treatment or in conjunction with this technique. The prolonged heating isin the nature of a pasteurization process. Excessive heating tends to destroy the aromatic smoking qualities of the tobacco. The heating is best carried out in a closed area and may be done under pressure. It can be conveniently done in an inert atmosphere such as nitrogen or carbon dioxide but this is not essential. Hot vapor such as steam may be blown through the tobacco. The temperature may range from 60 C. to 160 C. during a time of fifteen minutes to six hours. Clearly, greater time of heating will allow the use of a lower temperature and vice versa. Likewise, the use of chemical treatment together with heat allows a shorter exposure to heat.

The following examples illustrate in detail the trea ment of tobacco according to this invention prior to its contact with adhesive material in the manufacture of tobacco sheets.

Example 1 In a preferred example of a method according to this invention a measured quantity of finely divided tobacco is added to three times its weight of water. The mixture is heated in a closed container. Heat is provided by boiling water or a steam bath. The heating period is about three hours and the temperature is maintained close to C.

Example 2 The treatment of tobacco is carried out in a closed container with a quantity of formalin equal to one percent of the weight of the tobacco added to the water.

Example 3 Finely divided tobacco is moistened with 2.5% of its weight of formalin. The mixture is heated in an open narrow mouth flask to remove excess formalin. A thermometer is inserted in the interior of the tobacco mass and the temperature is maintained at about C. for about an hour.

There have thus been described methods of treating tobacco to neutralize its adverse effect upon polysaccharide adhesive material and yet retain the desirable smoking qualities of the tobacco.

What is claimed is:

1. In the manufacture of tobacco sheet material wherein tobacco is contacted with polysaccharide adhesive material the steps of heating finely divided tobacco to a temperature between 60 C. and C. for a time greater than fifteen minutes and less than six hours and then contacting said heat treated finely divided tobacco with polysaccharide adhesive material.

2. In the manufacture of tobacco sheet material the method comprising the steps of heating finely divided tobacco in an inert atmosphere between one and six hours at a temperature between 80 C. and 160 C. and then contacting said finely divided, heat treated tobacco with polysaccharide adhesive material.

3. In the manufacture of tobacco sheet material 3 wherein tobacco is'contacted with polysaccharide adhesive materialthe =stcpyof trcatingfinely "divided-tobacco with an aqueous aldehyde solution and aldehyde vapor and then contactingsaid finely divided, aldehyde treated tobacco with 'polysacchari'de' adhesive material.

'4: In themanufacture of tobacco sheet material the methodcomprising in combination the steps of "heating finely dividedtobacco between 60 C; and "160? C. for a time between fifteen minutes and six hours, treating said finely divided-'tobaccowith an aqueous aldehyde solution and aldehyde vapor and then contacting said finely divided tobacco, with polysaccharideadhesive rnaterial.

5; In the manufacture ottobacco sheet material in combination'the 'steps of treating finely divided tobacco with formaldehyt'le and contacting said formaldehyde treated 'finely dividedtobaccowith polysaccharide ad hesive material.

6. In the manufacture of tobacco sheet material in combination the steps ofheating an. aqueous slurry of finely divided tobacco betweenfit'teen minutes and six hours withina temperaturerange of 60? C. and 160C.

andthen contactingjsaid. slurry oifinely divided tobacco with polysaccharide adhesive material? 7. In the manufacture of tobacco sheet material in combinationthe steps of heating finely dividedtobaccotemperature range between C. and C. and the r contacting said heated finely divided tobacco with "sodium carboxymethyl cellulose adhesive material.

References Cited in the .file of this patent UNITED V STATES PATENTS 3,673 Huse July 22, 1844 877,698 Bedortha Jan. 28, 1908 2,613,672 Sortoretto etal Oct. 14, 1952 FOREIGN PATENTS 10,557 Great Britain Dec. 4, 19 1-3 

1. IN THE MANUFACTURE OF TOBACCO SHEET MATERIAL WHEREIN TOBACCO IS CONTACTED WITH POLYSACCHARIDE ADHESIVE MATERIAL THE STEPS OF HEATING FINELY DIVIDED TOBACCO TO A TEMPERATURE BETWEEN 60* C. AND 160* C. FOR A TIME GREATER THAN FIFTEEN MINUTES AND LESS THAN SIX HOURS AND THEN CONTACTING SAID HEAT TREATED FINELY DIVIDED TOBACCO WITH POLYSACCHARIDE ADHESIVE MATERIAL. 